Its hard to tell really, both projects will likely have progressed significantly in the next 5 years. As it stands currently I think NEO will have the edge due to superios speeds and scalability, but if Ethereum can actually get people to agree on scaling solutions and push one forward then they can likely keep hold of their lead.

I think no matter what happens, both blockchains will have significantly increased use cases and if the market cap rises like people think it will, both could have huge market caps.